window.cpp Example File

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  #include <QtWidgets>
  #include "window.h"

  Window::Window()
  {
      thread = new RenderThread();

      label = new QLabel();
      label->setAlignment(Qt::AlignCenter);

      loadButton = new QPushButton(tr("&Load image..."));
      resetButton = new QPushButton(tr("&Stop"));
      resetButton->setEnabled(false);

      connect(loadButton, SIGNAL(clicked()), this, SLOT(loadImage()));
      connect(resetButton, SIGNAL(clicked()), thread, SLOT(stopProcess()));
      connect(thread, SIGNAL(finished()), this, SLOT(resetUi()));
      connect(thread, SIGNAL(sendBlock(Block)), this, SLOT(addBlock(Block)));

      QHBoxLayout *buttonLayout = new QHBoxLayout();
      buttonLayout->addStretch();
      buttonLayout->addWidget(loadButton);
      buttonLayout->addWidget(resetButton);
      buttonLayout->addStretch();

      QVBoxLayout *layout = new QVBoxLayout(this);
      layout->addWidget(label);
      layout->addLayout(buttonLayout);

      setWindowTitle(tr("Queued Custom Type"));
  }

  void Window::loadImage()
  {
      QStringList formats;
      foreach (QByteArray format, QImageReader::supportedImageFormats())
          if (format.toLower() == format)
              formats.append("*." + format);

      QString newPath = QFileDialog::getOpenFileName(this, tr("Open Image"),
          path, tr("Image files (%1)").arg(formats.join(' ')));

      if (newPath.isEmpty())
          return;

      QImage image(newPath);
      if (!image.isNull()) {
          loadImage(image);
          path = newPath;
      }
  }

  void Window::loadImage(const QImage &image)
  {
      QDesktopWidget desktop;
      QImage useImage;
      QRect space = desktop.availableGeometry();
      if (image.width() > 0.75*space.width() || image.height() > 0.75*space.height())
          useImage = image.scaled(0.75*space.width(), 0.75*space.height(),
                                  Qt::KeepAspectRatio, Qt::SmoothTransformation);
      else
          useImage = image;

      pixmap = QPixmap(useImage.width(), useImage.height());
      pixmap.fill(qRgb(255, 255, 255));
      label->setPixmap(pixmap);
      loadButton->setEnabled(false);
      resetButton->setEnabled(true);
      thread->processImage(useImage);
  }

  void Window::addBlock(const Block &block)
  {
      QColor color = block.color();
      color.setAlpha(64);

      QPainter painter;
      painter.begin(&pixmap);
      painter.fillRect(block.rect(), color);
      painter.end();
      label->setPixmap(pixmap);
  }

  void Window::resetUi()
  {
      loadButton->setEnabled(true);
      resetButton->setEnabled(false);
  }